GFED4 global monthly burned area at 0.25 degree spatial resolution available at https://daac.ornl.gov/VEGETATION/guides/fire_emissions_v4_R1.html from Giglio et al. (2013) 

Giglio, L., J. T. Randerson, and G. R. van der Werf, Analysis of daily, monthly, and annual burned area using the fourth-generation global fire emissions database (GFED4), Journal Of Geophysical Research: Biogeosciences, Vol. 118, 317–328 https://doi.org/10.1002/jgrg.20042, 2013.
